Sunday, 16 August 2020

Sunn Beta Pre Amp

 Ok, let's release the beast. Two layouts. One stock for iether Bass or Lead cap values.

And another one with a Beta/Lead switch. Since I'm not a big fan of offboard wiring I decidied to simplify things a bit. Lead cap values is always in circuit and with a 4PDT switch you can switch in four caps in parallel so it matches up with Bass values. Some values differs in few hundred pico farad or a few nano farad but the overall difference is minimal. And in theory you could use a SPST switch....

It also has an onboard charge pump for 15v/-15 operation.

This going to be the last layout I will post in a while since I'm going back to work tomorrow but this and a few other layouts should keep some of you occupied....;-) 


*Edit*

MTK once again outdid himself! Here is a short demo of Lead/Bass switch version.


Stock layout.

 
 
 
 
Layout with Lead/Bass switch
 
 
 

 
 


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15 comments:

  1. MTK16 August 2020 at 20:27

    This was a 5 hour project. I don't even wanna know how long this layout took. lol Thanks for finding time for this one, man. I appreciate it.

    Board - https://i.imgur.com/gJyK7Cz.jpg

    Demo - https://www.youtube.com/watch?v=dReZ1UGBj2k

    ReplyDelete
    Replies
    1. fuzzhead16 August 2020 at 20:34

      You are a madman!
      Thanks for taking YOUR time to building it and fix the charge pump issue.
      Tagged!

      Delete
    2. MTK16 August 2020 at 22:55

      Happy to help. I was talking with Alex about how to get more gain out of it and he recommended taking out R1 and R5 and using jumpers. That did the trick. I only jumpered R1 and it was enough extra gain for me. Just took this circuit to 11 in my book.

      Delete
    3. Unknown17 August 2020 at 02:44

      Hi MTK. By R1 you mean the 47k resistor in input? And R5?

      Delete
    4. AlexS17 August 2020 at 03:15

      I'd build it stock and see if you need more distortion.
      The 120k at S-13 and the 1M at S-18 make up the gain stage after the drive pot. Or maybe you can bump up the gain stages on the 4069. You don't want to accidentally change the tone in some drastic way.

      I bet since this is a preamp, it would be a good candidate for using a boost pedal.

      Now the tone control, what's going on there?

      Delete
  2. stefano26 August 2021 at 09:43

    What is the little black hole under IC5?

    ReplyDelete
  3. Unholy Audio22 October 2021 at 04:13

    Done: https://www.youtube.com/watch?v=FK6Xl9_B0W0

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  4. strangeloop24 October 2022 at 19:57

    Howdy, folks! Can anyone out there share IC voltages on this bad boy? I have it built and am getting a heavily gated, and just generally crappy-sounding effected signal, as well as constant, really loud 7K-ish and 14K-ish tones. Any help would be appreciated!

    ReplyDelete
    Replies
    1. thefunkmeister12 July 2024 at 23:51

      hey there, i just built it and have the same issue (somewhat), did you end up getting it going?

      Delete
  5. Haelon19 January 2023 at 03:36

    Hi! I'm trying to replicate the Lead/Bass circuit in Proteus, but I'm having trouble reading the layout without the schematics, do any of you guys have the schematics to share?

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    Replies
    1. fuzzhead20 January 2023 at 12:25

      Check this out.
      http://effectslayouts.com/wp-content/uploads/2020/01/SunnBeam-build-doc.pdf

      Delete
  6. Tom19 January 2023 at 04:41

    It looks like several are available on freestompboxes.org

    ReplyDelete
  7. Rathma2416 March 2023 at 09:45

    Hi!
    What do you think, can I use MAX1044 or ICL7660 instead of LT1054?

    ReplyDelete

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